Hiroyuki Yamanaka

Two curcuminoid pigments from Curcuma domestica

Abstract Two new pigments were isolated from fresh rhizomes of turmeric ( Curcuma domestica Val.). Their structures were determined to be 1-(4-hydroxy-3-methoxyphenyl)-7-(3,4-dihydroxyphenyl)-1,6-heptadiene-3,5-dione and 1,7-bis (4-hydroxyphenyl)-1,4,6-heptatrien-3-one by spectroscopic methods.

Off-flavor production in frozen strawberries

Abstract The development of off-flavor in frozen-thawed strawberries was attributed to the production of H2S. The identity of H2S was verified both chemically, through its reaction with lead acetate, and using gas chromatography-mass spectroscopy analyses. The duration of the production of H2S was longer in berries stored at −40 °C and −80 °C than in those stored at −20 °C. Because the amount of sulfide ion in frozen strawberries was lower than that in fresh berries, and because K2S addition resulted in further increases in the production of H2S, it is likely that H2S evolution is due to the decrease in pH of the cytosol caused by the disruption of cells by freezing, resulting in the release of sulfide ion as H2S. Vigorous crushing of fresh berries also gave rise to the production of H2S.